Monocytes from the peripheral blood of patients with Gaucher's Disease and normal subjects will be put into monolayer tissue cultures. Attempts will be made to determine whether the patients' cells accumulate increased amounts of the glycolipid, glucocerebroside. In some experiments, the monocytes will be "fed" radioactively labeled glucocerebrosidase, prepared from human placenta, using various carriers, including gamma-globulin-coated resealed red cell membranes, various of types of liposomes, and enzymes coupled to other carrier systems. The ability of such an exogenously introduced enzyme to survive in the cell, and for it to function by breaking down glucocerebroside in the cell will be examined.